Dissociative excitation of HgII halides by Xe(3P2) and Xe(3P1)

Abstract

Rate constants for the production of electronically excited state products from the reaction of Xe(³P₂) with several methylmercury and mercuric halides have been measured in a flowing afterglow at elevated temperatures. The most important product is HgX(B²Σ⁺), X = Cl, Br or I for all reagents studied. Minor amounts of HgX(D, C²Π) and XeX^* state emissions also were observed. Sensitization experiments with Xe(³P₁) and HgCl₂ gave the same result. For HgCl₂ and HgBr₂, the rate constants for HgX(B) formation are large (ca. 10^–9 cm³ molecule^–1 s^–1), which suggests that quenching of Xe^* gives HgX^* with a branching ratio of nearly unity. The rate constants for HgX(B) formation from CH₃HgX compounds are approximately an order of magnitude smaller than for the HgX₂ compounds. Reactions of both CH₃HgX and HgX₂ compounds with He(2 ³S), Ne(³P₂), Ar(³P₂) and Kr(³P₂) gave predominantly Hg emission.